Conventionally, known has been a solder wire bobbinless coil including a hollow columnar main body provided by detaching a bobbin from a bobbin coil formed by a solder wire wound around the bobbin (for example, see Patent Document 1). In the solder wire bobbinless coil, a portion of one end surface of the main body excluding a hollow portion, the outer circumferential surface of the main body, and the other end surface thereof are covered by a heat-shrinkable film, and the solder wire is drawn out from the hollow portion that is not covered by the heat-shrinkable film and is opened.